One of the most fascinating studies which can engage the attention of a geologist is the literature of his science of a century or so ago. Some of the problems then discussed have long since received their answers and been laid aside; others, like ghosts, refuse to be laid and are still with us. But in all cases the point of view is so different from that of the present time, and in many cases the arguments adduced are so quaint and curious, that the picture of the geological science of those early days is one of peculiar interest. The theological influence of the cosmogonist permeates much of the writings of this early time, and there are scores of treatises on the constitution and history of the earth, in which the authors have drawn their material in part from a nodding acquaintance with certain of the salient phenomena of nature, . . .